Last month, Brendan Nyhan, a professor of political science at Dartmouth, published the results of a study that he and a team of pediatricians and political scientists had been working on for three years. They had followed a group of almost two thousand parents, all of whom had at least one child under the age of seventeen, to test a simple relationship: Could various pro-vaccination campaigns change parental attitudes toward vaccines? Each household received one of four messages: a leaflet from the Centers for Disease Control and Prevention stating that there had been no evidence linking the measles, mumps, and rubella (M.M.R.) vaccine and autism; a leaflet from the Vaccine Information Statement on the dangers of the diseases that the M.M.R. vaccine prevents; photographs of children who had suffered from the diseases; and a dramatic story from a Centers for Disease Control and Prevention about an infant who almost died of measles. A control group did not receive any information at all. The goal was to test whether facts, science, emotions, or stories could make people change their minds.

The result was dramatic: a whole lot of nothing. None of the interventions worked. The first leaflet—focussed on a lack of evidence connecting vaccines and autism—seemed to reduce misperceptions about the link, but it did nothing to affect intentions to vaccinate. It even decreased intent among parents who held the most negative attitudes toward vaccines, a phenomenon known as the backfire effect. The other two interventions fared even worse: the images of sick children increased the belief that vaccines cause autism, while the dramatic narrative somehow managed to increase beliefs about the dangers of vaccines. “It’s depressing,” Nyhan said. “We were definitely depressed,” he repeated, after a pause.

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It’s the realization that persistently false beliefs stem from issues closely tied to our conception of self that prompted Nyhan and his colleagues to look at less traditional methods of rectifying misinformation. Rather than correcting or augmenting facts, they decided to target people’s beliefs about themselves. In a series of studies that they’ve just submitted for publication, the Dartmouth team approached false-belief correction from a self-affirmation angle, an approach that had previously been used for fighting prejudice and low self-esteem. The theory, pioneered by Claude Steele, suggests that, when people feel their sense of self threatened by the outside world, they are strongly motivated to correct the misperception, be it by reasoning away the inconsistency or by modifying their behavior. For example, when women are asked to state their gender before taking a math or science test, they end up performing worse than if no such statement appears, conforming their behavior to societal beliefs about female math-and-science ability. To address this so-called stereotype threat, Steele proposes an exercise in self-affirmation: either write down or say aloud positive moments from your past that reaffirm your sense of self and are related to the threat in question. Steele’s research suggests that affirmation makes people far more resilient and high performing, be it on an S.A.T., an I.Q. test, or at a book-club meeting.

Normally, self-affirmation is reserved for instances in which identity is threatened in direct ways: race, gender, age, weight, and the like. Here, Nyhan decided to apply it in an unrelated context: Could recalling a time when you felt good about yourself make you more broad-minded about highly politicized issues, like the Iraq surge or global warming? As it turns out, it would. On all issues, attitudes became more accurate with self-affirmation, and remained just as inaccurate without. That effect held even when no additional information was presented—that is, when people were simply asked the same questions twice, before and after the self-affirmation.